Apparatus for treating slimes.



D. COLE.

APPARATUS 'FOR TREATING SLIMES.

APPLICATION FILED MAR. 24. 1915.

Patented NOV. 21, 1916.

3 SHEETS-SHEET 1.

mwsmz 37720222167"- fiM 61 D COLE.

APPARATUS FOR TREATING SLIMES.

APPLICATION man MAR- 24. 1915.

1,205,321 Patented Nov. 21, 1916.

3 SHEETS-SHEET 2- D. COLE.

APPARATUS FOR TREATING SLIMES.

APPLICATION FILED MAR.24.19.15.

Patented Nov. 21', 1916.

a SHEETS-SHEET 3.

DAVID COLE, OF TUCSON, ARIZONA.

I APPARATUS FOR TREATING SLIMES.

Specification of Letters Patent.

Patented Nov. 21, 1916.

Original application filed April 12, 1913, Serial No. 760,702. Dividedand this application filed March 24, 1915. Serial No. 16,702.

To all whom it may concern Be it known that I, DAVID COLE, a citizen ofthe United States, residing at Tucson,

U in the county of Pima and State of Arizona, have invented certain newand useful Improvements in Apparatus for Treating Slimes, of which thefollowing is a specification.

This application is a division of my copending application, Serial No.760,702, filed April 12, 1913, and relates to the preferred form ofapparatus for carrying out the art or method of classifying andconcentrating slimes of sulfid copper ores and similar ores, describedand claimed in said parent a plication.

In or er that the general principle involved in the invention may befully understood I shall outline briefly the nature of the material tobe handled, and certain characteristics of its behavior in water.

In treating sulfid copper ores by the method hitherto in general use,the greatest unavoidable losses in metal have occurred in that portionof the rejections known as slimes. Slimes may generally be defined as amixture of water and comminuted ore and mineral capable of passingreadily a screen having openings twenty-five tenthousandths (00025) of,an inch square. Heavy tonnages of such slimes must be I handled in allcases in which the metallic elements to be recovered are so disseminatedthroughout the ore as to require fine grinding. a y 'The diiiiculty inhandling such slimes arises fron. the presence in them of a largepercentageof what have come to be known in the art as colloids, ascontradistinguished from crystalloids or crystalline metallic sulfidsvand other generally crystalline metallic compounds. As a general rulethe socalled colloids contain a relatively small percentage of metallicvalues in sulfid form andptheir presence alwaysgreatly hinders he'con'centration of such values from the crystalline material because of acharacteristic flocculent arrangement which the colloids assume almostas soon as the slime comes to rest and solids begin to settle.

- By a careful series of tests I have determined.;thecharacteristicbehavior of such slimesduring the settling action. Whenthe settling first begins, and before the colloids have had anopportunity to assume their flocculent arrangement, the settlin of thecrystalline particles is very little impeded by the colloids, and takesplace rapidly, so

that a small percentage of the crystalloids, generally the largerparticles, readily settles to the bottom of the relatively deep vesselscommonly used. As the colloids assume their characteristic flocculentform the flakes be in to arrest and sustain the smaller crystalloldparticles, and as the flocculence.

becomes more pronounced and the flakes settle 1nto closer contact withone another,

larger and larger crystalloid particles are arrested. This settling ofthe flakes and increased density of the colloid mass takes place slowly,because of the retarded outflow of water from between the flakes, but bythe time it has progressed to a point at which the solids form about 7%of the mixture the settling of the crystalloids is greatly impeded andby the time the solids form 10% of the mixture all settling of theslimed crystalloids through the floc'-- culent colloids seems to cease.In all types of cones, spitzkastens and other prior devices used intreating this class of material much thickening of the mixture bysettling of the flocculent colloids necessarily takes place prior to thesettling out of a large percentage of the crystalloids on account oftheir relatively great depth, and in these The above considerations havesuggestedto me the impraeticability of successful concentrating slimescontaining colloids by the present practice of thickening the slime indeep vessels prior to feeding it to the slimers and the like; and havesuggested the desirability of effecting a preliminary separation andremoval of the colloids by taking advantage of the early portion of thesettling cycle of the slime in the presence of an excess of water invery shallow separately thus leaving a comparatively large percentage ofclarified water to be again used as such.

I have successfully carried out my process by making use of theapparatus claimed in the present application, which includes a largesettling tank approximately six inches deep to which I feed a diluteslime mixture, for example one containing about 5% of combinedcrystalloid and colloid solids. The mixture is fed in at one side of theshallow tank, flows slowly across the tank and is discharged ,over awide shallow overflow at the opposite side of the tank. The movement ofthe slime across the tank is characterized generallyby a whole flow ascontradistinguished from a surface flow.

The Shallowness of the tank and the dilute nature of the slime cause asettling out of the crystalloids early in the path of the mixture acrossthe tank, the colloids being carried farther across the tank because oftheir greater tendency to remain in suspension.

Various slightly different methods of availing of the broadcharacteristic principle of my invention have. been used by me, the mostsatisfactory involving a repetition of the settling process to secure abetter separation and incidentally to recover a proportion of the waterused in the process.

.The simplest method is of course to make use of a relatively narrowtank with a correspondingly small number of belts, sufficient to includethe zone of settling of the crystalloids and usually a limited portionof the zone in Which mixed crystalloids and colloids are precipitated.The bulk of the colloids thus overflow, from the tank as tailings withthe water, the precipitated material being the concentrates. In order tosave part of the water it is preferable however to make use of a muchwider tank having a correspondingly larger number .of belts, the tankbeing so designed that all the solids both crystalloid and colloid aresuccessively precipitated and clear-water is discharged at the overflow.The belts will then lie in three zones (1) that in which practicallyonly crystalloids are precipitated, (2) that in whichsubstantial-proportions of both crystalloids and colloids areprecipitated, and (3) that in which practically only colloids areprecipitated- The different classes of material are thus removed fromthe tank by three different sets of belts, and may then be individuallytreated.

To secure a practical elimination of colloids the water discharged atthe overflow is fed together with the precipitates from zones 1 and 2 toa second and narrower tank. Because of the dilute nature of the mixture,complete precipitation takes place in this tank and clear wateroverflows, and 1 mineral values it may be subjected to appropriatesubsequent treatment to recover them, such as flotation processes,'orchemical leaching.

I shall now describe in detail the apparatus which I have developed as ameans for carrying out my new art or method.

In the accompanying drawings, Figure 1 is a section through a settlingtank embodying my invention, the plane of section being taken on theline 1-1 of Fig. 2; Fig. 2 is an elevation of the right end of the samelooking from the right as viewed in Fig. 1; Fig. 3 is an enlargedfragmentary view of a portion of Fig. 1, showing the position of thebelt on the bottom of the settling tank, and in the return basin; Fig. 4is a View of the underside of a belt which I prefer to use in my devicefor the first two belts counted from the supply side; Fig. 5 is a planview of the tank showing the general arrangement of the belts, locationof the supply and overflow, etc. Fig. 6 is a flow diagram of thesimplest method of practising my invention. Fig. 7 is a flow diagram ofthe preferred method of practising my invention; and Fig. 8 is afragmentary vertical section of a modified form of settling tank.

Referring to ,the drawings, it will be noted that the settling tankproper. consists of a bottom or floor 1 flat at its middle portion andgradually sloping upward toward the ends. The sides of the tank 2 areprovided with the supply or inlet chamber or enlargewalls 2 in orderthat material may flow from the tank in a wide thin sheet. Thearrangement of the sides 2, overflow 4 and of I,

plurality of belts the lower sides of the Running longitudinally in thetank are a first two belts in the series being preferably formed withthe V'-shaped ribs or flights 6'. The function of these flights is tomove toward the edge of-the belt any relatively coarse material whichmay'find its way beneath the same so that the belts will not be liftedaway from the bottoni of the tank by the accumulation of materialbeneath'them. The belts are arranged in pairs, successive pairs beingdriven in opposite directions. 'Each beltruns at one end on a live drumor pulley 7 and at the opposite end on an idle drum or pulley 8, thereturn run of the belt being guided by snub pulleys 9 through a shallowwaterbasin 10 designed to clean and prevent undue wear in the belts.Thespray pipes 11 are provided to wash material ofi' the belts as theyleave the live pulleys so as to prevent the belts from carrying anysolid material on the return run. The live pulleys 7 are mounted in thehoppers or boxes 12 adapted to receive any solid material conveyed outof the-tank by the belts, and discharge it through openings 13 intosuitable.

-each sprocket 15, or in other words for each pair of belts ifnecessary, and each reducing train receives its power from one of theline shafts18 through suitable individual changespeed devices indicatedat 19. The line shafts are driven by motors such asthe electric motorsindicated by-dotted lines at 20.. The speed of movement of each pair ofbelts may be subjected to individual regulation, by means of the changespeed devices 19.

The purpose of arranging the alternate pairs of belts to run in oppositedirections is'to neutralize the eflect of the moving belts upon the flowof material acrossthe tank.

Obviously they might all be run in the same direction, but I prefer thearrangement described. Although the dimensions of the tank and belts aresubject to considerable variation I have secured very satisfactoryresults with a tank in which the belts travel about 35 feet under thesurface of material in the tank, the belts moving at a speed of about 35feet per minute. The width of each pair of belts in this device isapproximately 50 inches and the number of pairs of belts used and degreeof shallowness is dependent upon the nature of the material to'behandled and the time required to complete the cycle desired and themethod of treatment adopted as already suggested. 'The dimensions givenare only illustrative and I do not limit myself to them.

Where it is desirable to do so construct these machines so that thereturn run of belt 5 passes through a second tank 21 underneath thefirst tank 1', and substantially identicaltherewith in form andfunction. See Fig. 8. Thus a double machine is formed without increasein floor space and with only moderate. increase in height. However, itis necessary in the case of the lower belt to provide a squeegee 22 setupon the belt-and lubricated with water from a spray pipe 23 for thepurpose of removing the material-brought up to this point by the belt,This squeegee effect is produced by applying a piece of thin rubber or apiece of rubber belting'upon the smooth surface of the belt at an anglewith its travel'so that the material carried on its surface is causedtcflow oif'to one side of the belt and be i deposited in the hopper 12and be adapted to pass out of the spout 13 in the-same manner andcondition as the product produced on the belt emerging" from the upperbasin. Where a large tonnage is to be handled this arrangementeconomizes space and is desirable.

As already suggested the principle involved in the process and apparatusillustrated for practising it, may be utilized in a number of relationsdiffering in detail but fundamentally similar.

In Fig. 6, I illustrate diagrammatically a single tank A having eightbelts. The feed from the mill enters at B. The tailings (colloids)overflow at C with the bulk of the water. The concentrates(crystalloids) are precipitated and are carried out with a minimum ofwater by'the belts (here assumed all to move in the same direction forease in making the. diagram). The concentrates from different groupsof'belts are fed to different clean up machines D, E, F, each of whichmay, if desired, be particularly adapted to the class of materialprecipitated'on the corresponding belts in the tank.

In Fig. 7, I illustrate diagrammatically a sixteen belt tank G. The feedfrom the mill enters at H. Clear water overflows at I. The first sixbelts discharge crystalloids at J; the next five belts'dischargecrystalloids and colloids in varying proportions at K; and the last fivebelts discharge colloid tailings at L. The water overflowing at I andthe solid material from J and K are fed to a six belt tank M at N. Clearwater overflows at O and may be used many desired manner. The first beltdischarges at P; the second at Q and the third and fourth at R tocorresponding clean-up machines S, T, and U. The fifth and sixth beltsdischarge colloid tailings at V.

The materialfed to tanks A and G contains about of solids or less in thecase of very fine materials. The material fed to tank M is usually muchmore dilute, and this tank efl'ects a very complete removal of thecolloids because of such dilution and because of the comparatively smallamount of colloid material present.

As a general rule belts intended to withdraw precipitated colloids mustbe run slower than is necessary for similar belts for removingcrystalloids to avoid eddies which conveyer belt running on saidpulleys, one

run of said belt dipping into said tank and traveling substantiallyhorizontally on the bottom thereof in a direction transverse to thedirection of flow of ,material in said tank, and the return run of saidbelt passing outside said tank.

2. In a device for treating slimes, the combination of a shallow tankclosed against any but a transverse flow 'across'the same; means fordelivering slime in an extended shallow stream to one side of said tank;a plurality of sets of belt driving and guiding pulleys; and a pluralityof endless adjacent and substantially parallel conveyer belts each beltrunning on a -corresponding set of pulleys, one run of each belt dippinginto said tank and traveling on the bottom thereof substantiallyhorizontally in a direction transverse to the direction of flow ofmaterial in said tank, and the return runs of said belts passing outsidesaid tank.

3. In a device for treating slimes, the combination of a shallow tankclosed against any but a transverse flow across the same; means fordelivering slime in an extended shallow stream to oneside of said tank;a plurality of sets of belt driving and guiding pulleys; a plurality ofendless adjacent and substantially parallel conveyer belts each beltrunning on a corresponding set of pulleys, one run of eachbeltdippingjnto said tank and traveling on the bottom thereofsubstantially horizontally in a direction transverse to the direction offlow of material in said tank, and the return runs of said belts passingoutside said tank, and driving means for said belt driving pulleys fordriving certain adjacent belts in opposite directions whereby thecreation of disturbing ourrents by the movement of the belts is pre- 7vented.

4. In a device for treating slimes, the combination of a shallow tankclosedagainst 3 any but a transverse flow across the same;

, leys, one run of each belt dipping into said tank and traveling on thebottom thereof transverse to the direction of flow of material in saidtank, and the return runs of' said belts passing outside said tank; andindividual driving means forgroups of adjacent belt driving pulleys,each driving.

means including va change speed device, whereby the'speeds of groups ofbelts are subject to individual regulation.

5. In a device for treating slimes, the combination of a pair ofsuperposed shallow settling tanks each closed against any but atransverse flow across the same means for delivering slime in anextended shallow stream to one side of each tank; a plurality of endlessadjacent and-substantially parallel conveyer belts one run of each beltdipping into one tank and traveling on the bottom thereof in a directiontransverse to the flow therein and the other run of each belt dippinginto the other tank and returning on the bottom thereof in a directiontranssubstantially horizontally in a direction verse to the flowtherein; and means for guiding and driving said belts.

In testimony whereof I have name to this specification.

DAVID COLE.

